Lucene 6 - 推荐使用术语词汇表存储数字字段的方法

Question

In Lucene 6, LongField and IntField have been renamed to LegacyLongField and LegacyIntField , deprecated with a JavaDoc suggestion to use LongPoint and IntPoint classes instead.

However, it seems impossible to build a term vocabulary (=enumerate all distinct values) of these XPoint fields. Lucene mailing list entry confirms it

PointFields are different than conventional inverted fields, so they also don't show up in fields(). You cannot get a term dictionary from them.

As a third option, one can add a field of class NumericDocValuesField , which as far as I know, also doesn't provide a way of building term vocabulary.

Is there a non-deprecated way of indexing a numeric field in Lucene 6, given the requirement to build a term vocabulary?

Answer 1

In my case I just duplicated the field once as LongPoint and once as a stored non-indexed field both fields with the same name.

in my case it is roughly

doc.add(new NumericDocValuesField("ts", timestamp.toEpochMilli()));
doc.add(new LongPoint("ts", timestamp.toEpochMilli()));
doc.add(new StoredField("ts", timestamp.toEpochMilli()));

It is a bit ugly, but think of it as adding an index to the stored field. These field types can use the same name without interfering.

The DocValues for document age based scoring and the LongPoint for range queries.

Answer 2

I had the same issue and finally found a solution for my use case - I'm indexing, not storing, a LongPoint:

doc.add(new LongPoint("time",timeMsec));

My first idea was to create the query like this:

Query query = parser.parse("time:[10003 TO 10003]");
System.err.println( "Searching for: " + query + " (" + query.getClass() + ")" );

But this will not return ANY document, at least not with the StandardAnalyzer and the default QueryParser :-(

The printout is: "Searching for: time:[10003 TO 10003] (class org.apache.lucene.search.TermRangeQuery)"

What works, however, is creating the query with LoingPoint.newRangeQuery() :

Query query = LongPoint.newRangeQuery("time", 10003, 10003);
System.err.println( "Searching for: " + query + " (" + query.getClass() + ")" );

This prints: "Searching for: time:[10003 TO 10003] (class org.apache.lucene.document.LongPoint$1)". So the standard QueryParser is creating a TermRangeQuery instead of a LoingPoint range query. I'm new to Lucene so don't understand the details here, but it would be nice for the QuerParser to support LongPoint seamlessly...